An Investigation of Alternative Path Planning Strategies for Machining of Nickel-Based Superalloys
An Investigation of Alternative Path Planning Strategies for Machining of Nickel-Based Superalloys
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镍基高温合金加工替代路径规划策略的研究
DOI：
10.1016/j.promfg.2015.09.032
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
L. Mears
中科院分区：
文献类型：
--
作者：
Abram Pleta;Durul Ulutan;L. Mears
镍基高温合金在需要高强度、高耐腐蚀性和抗蠕变的高温应用中起着至关重要的作用。这些环境主要存在于航空航天、核电和燃气轮机行业。由于它们的特性使它们适合最终使用，它们的制造仍然是一个挑战。在镍基高温合金的加工中，由于切削力大，刀具磨损严重，极大地降低了其可加工性。虽然最近已经有多项关于这类合金加工的研究，但该领域仍然非常未被探索。由于以往的大多数研究都集中在寻找最佳加工参数以减少加工难度，同时保持刀具路径不变，所以对刀具路径方法的研究有限。另一种刀具路径--摆线铣削已经被确定，以克服加工高温合金的困难，并将直线运动与均匀的圆周运动相结合，减少切屑负荷，以换取更长的加工时间。虽然这种方法被证明可以减少刀具的后刀面磨损，但它在切削线深度处存在缺口磨损。在这项研究中，作者提出并评价了一种新的刀具路径，称为变深度铣削(VDM)，以减少或消除镍基高温合金的缺口磨损。在这种方法中，整个刀具的轴向切割深度是以线性方式变化的，以向上倾斜的方式从最大切削值深度到零。这项工作表征了摆线铣削和变深度铣削技术的效果，并将它们与传统的铣削技术-端面铣削进行了比较。为了比较这些可供选择的直接到端面铣削的刀具路径方法，作者使用相对较新的度量来提供生产率和效率特征的更具代表性的比较：单位刀具磨损的体积材料去除量(MR/VB)和单位刀具磨损的材料去除率(MRR/VB)。研究发现，摆线铣削在生产率方面优于端面铣削，在相同刀具磨损量的情况下，摆线可以加工出比端面铣削至少多7倍的材料，而效率与端面铣削相同。结果表明，VDM以略微降低生产率和效率为代价，消除了刀具缺口磨损的形成。
Nickel-based superalloys play a crucial role in elevated temperature applications where high strength and high resistance to corrosion and creep resistance are required. These environments are largely found in the aerospace, nuclear power and gas turbine industries. Due to the properties that make them suitable for their end use they remain a challenge to manufacture. In the machining of nickel-based superalloys high cutting forces and tool wear occur greatly reducing their machinability. Although there have been multiple recent studies on the machining of such alloys, the field remains vastly unexplored. A limited amount of research has been done in tool path methods, as most previous research focuses on finding optimal machining parameters to curtail the difficulties in machining while keeping the tool path constant. An alternative tool path, trochoidal milling, has been identified to combat the difficulties in machining superalloys and combines linear motion with uniform circular motion, reducing chip load in exchange for increased machining time. Although this method has been shown to reduce flank wear on tools it suffers from notch wear at the depth of cut line.In this study the authors propose and evaluate a new tool path termed variable depth milling (VDM) to reduce or eliminate the occurrence of notch wear in nickel-based superalloys. In this method the axial depth of cut is varied across the tool in a linear fashion, progressing from a maximum depth of cut value to zero in an upward ramping fashion. This work characterizes the effects of trochoidal milling and variable depth milling techniques and compares them against a traditional milling technique, end milling. In order to compare these alternative tool path approaches directly to end milling the authors utilize relatively new metrics to provide a more representative comparison of productivity and efficiency characteristics: volumetric material removal per unit tool wear (MR/VB) and the material removal rate per unit tool wear (MRR/VB). It was found that trochoidal milling was superior to end milling in terms of productivity, where trochoidal could machine at least seven times more material than end milling with the same amount of tool wear with similar efficiency as end milling. It was demonstrated that VDM eliminated the formation of notch wear in the cutting tool at the expense of a slight decrease in productivity and efficiency.